Role of Clostridium Difficile in calf diarrhea and its potential implications to public health
Bibliographic record
Abstract
The first study investigated the clinical significance of 'Clostridium difficile' in calf diarrhea and the relatedness between bovine and human 'C. difficile' PCR ribotypes. A retrospective case-control study involving 102 dairy farms in Ontario was performed with fecal samples from 134 diarrheic and 144 control calves. The isolation of 'Clostridium difficile' and the detection of its toxins A and B with a commercial ELISA test were conducted in a blinded fashion. 'Clostridium difficile ' was isolated from 31/278 calves; 11/144 (7.6%) with diarrhea and 20/134 (14.9%) controls (p=0.009). Toxins A or B, or both, were detected in feces from calves from 56.8% farms (58/102); 57/144 (39.6%) diarrheic calves and 28/134 (20.9%) controls (p=0.0002)PCR-ribotyping of 31 calf isolates revealed 8 distinct patterns; 7 identified in humans, of which, two have been associated with outbreaks of severe disease (PCR-types 017 and 027). In a second study, the potential causal association between ' C. difficile' and calf diarrhea was investigated with a prospective experimental infection study. Fourteen neonatal Holstein calves were inoculated with either a toxigenic strain of 'C. difficile' (PCR-type 077) (n=8) or placebo (n=6). Calves were monitored daily for signs of diarrhea, and were euthanized on day 6 or after the onset of diarrhea whichever came first. 'Clostridium difficile'-associated diarrhea was not recognized in the inoculated animals. Although 'C. difficile' PCR-type 077 was isolated from all infected calves, 'C. difficile' toxins were not consistently identified in feces using a commercial ELISA test. PCR-ribotyping analysis indicated that 4 calves under two days of age naturally harbored 5 different toxigenic 'C. difficile' ribotypes. Given the presence of 'C. difficile' spores in the feces of calves, a third study was conducted to investigate whether 'C. difficile ' could be cultured from commercial ground meat. The survival rate of spores treated at a cooking temperature (71°C) was also assessed. Sixty retail ground beef samples purchased in Ontario over a 10-month period were processed to identify 'C. difficile' spores. Toxigenic strains of 'C. difcile' were isolated from 20% (12/60) of the samples. PCR analysis showed 4 different ribotypes and similarity to human, bovine and canine ribotypes. Meat-derived 'Clostridium difficile' spores survived heating at 71°C. Although experimental oral infection of healthy calves with ' C. difficile' did not induce diarrhea within 6 days, this study indicates that 'C. difficile' is associated with calf diarrhea and that calves may be reservoirs of 'C. difficile' for humans. The PCR-ribotype similarity between bovine and human pathogenic isolates and the presence of 'C. difficile' spores in retail ground meat indicate that a risk of transmission between these two species might exist. The external validity of these epidemiological inferences needs further investigation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".